| 摘要 |
PURPOSE:To obtain worked products of good uniform shape by performing specified press working holding a material between the knockout retreating part of a die and the knockout retreating part of a punch. CONSTITUTION:When a material 5 to be worked is upsetted on a knockout 4'a slightly retreated from the bottom face of a hole 8a of a die 2', it is easily placed as a radius 10 is formed on the periphery of the bottom face of the hole 8a of the die 2'. It is rectified to upright attitude between a knockout 4b' which is slightly retreated from the bottom face of a hole 8b of a punch 6', and held surely. When press load is applied by pressing and lowering the punch 6' under this condition, the material 5 to be worked is press worked while being held in the center of forming die between retreating parts of knockouts 4a', 4b' of the die 2' and punch 6' from starting of upsetting to completion of press forming. Consequently, pressing load is applied concentrically to the material 5 keeping good balance, and good uniform products can be obtained. |
